package index;

/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Date;

import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.document.NumericField;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.IndexWriterConfig;
import org.apache.lucene.index.IndexWriterConfig.OpenMode;
import org.apache.lucene.index.Term;
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.FSDirectory;
import org.apache.lucene.util.Version;

import analyzer.ChineseAnalyzer;

/** Index all text files under a directory.
 * <p>
 * This is a command-line application demonstrating simple Lucene indexing.
 * Run it with no command-line arguments for usage information.
 */
public class IndexFiles {
	
	public static final String PATH_PREFIX = "D:/DH/software/lucene-3.6.1/";
	
	private IndexFiles() {}
	
	/** Index all text files under a directory. */
	public static void main(String[] args) {
//		String usage = "java org.apache.lucene.demo.IndexFiles" +
//				" [-index INDEX_PATH] [-docs DOCS_PATH] [-update]\n\n" +
//				"This indexes the documents in DOCS_PATH, creating a Lucene index" +
//				"in INDEX_PATH that can be searched with SearchFiles";
		String indexPath = PATH_PREFIX + "index";
//		String docsPath = PATH_PREFIX + "docs";
		String docsPath = "testdocs";
		boolean create = true;
//		for(int i=0;i<args.length;i++) {
//			if ("-index".equals(args[i])) {
//				indexPath = args[i+1];
//				i++;
//			} else if ("-docs".equals(args[i])) {
//				docsPath = args[i+1];
//				i++;
//			} else if ("-update".equals(args[i])) {
//				create = false;
//			}
//		}
		
		
		
//		if (docsPath == null) {
//			System.err.println("Usage: " + usage);
//			System.exit(1);
//		}
		
		final File docDir = new File(docsPath);
		
		if (!docDir.exists() || !docDir.canRead()) {
			System.out.println("Document directory '" +docDir.getAbsolutePath()+ "' does not exist or is not readable, please check the path");
			System.exit(1);
		}
		
		Date start = new Date();
		try {
			System.out.println("Indexing to directory '" + indexPath + "'...");
			
			Directory dir = FSDirectory.open(new File(indexPath));
//			Analyzer analyzer = new StandardAnalyzer(Version.LUCENE_31);
			Analyzer analyzer = new ChineseAnalyzer();
			IndexWriterConfig iwc = new IndexWriterConfig(Version.LUCENE_31, analyzer);
			
			if (create) {
				// Create a new index in the directory, removing any
				// previously indexed documents:
				iwc.setOpenMode(OpenMode.CREATE);
			} else {
				// Add new documents to an existing index:
				iwc.setOpenMode(OpenMode.CREATE_OR_APPEND);
			}
			
			// Optional: for better indexing performance, if you
			// are indexing many documents, increase the RAM
			// buffer.  But if you do this, increase the max heap
			// size to the JVM (eg add -Xmx512m or -Xmx1g):
			//
			// iwc.setRAMBufferSizeMB(256.0);
			
			IndexWriter writer = new IndexWriter(dir, iwc);
			indexDocs(writer, docDir);
			
			// NOTE: if you want to maximize search performance,
			// you can optionally call forceMerge here.  This can be
			// a terribly costly operation, so generally it's only
			// worth it when your index is relatively static (ie
			// you're done adding documents to it):
			//
			// writer.forceMerge(1);
			
			writer.close();
			
			Date end = new Date();
			
			System.out.println(end.getTime() - start.getTime() + " total milliseconds");
		
		} catch (IOException e) {
			System.out.println(" caught a " + e.getClass() +
					"\n with message: " + e.getMessage());
		}
	}

	/**
	 * Indexes the given file using the given writer, or if a directory is given,
	 * recurses over files and directories found under the given directory.
	 * 
	 * NOTE: This method indexes one document per input file.  This is slow.  For good
	 * throughput, put multiple documents into your input file(s).  An example of this is
	 * in the benchmark module, which can create "line doc" files, one document per line,
	 * using the
	 * <a href="../../../../../contrib-benchmark/org/apache/lucene/benchmark/byTask/tasks/WriteLineDocTask.html"
	 * >WriteLineDocTask</a>.
	 *  
	 *  @param writer Writer to the index where the given file/dir info will be stored
	 *  @param file The file to index, or the directory to recurse into to find files to index
	 *  @throws IOException
	 */
	static void indexDocs(IndexWriter writer, File file)
			throws IOException {
		// do not try to index files that cannot be read
		if (file.canRead()) {
			if (file.isDirectory()) {
				String[] files = file.list();
				// an IO error could occur
				if (files != null) {
					for (int i = 0; i < files.length; i++) {
						indexDocs(writer, new File(file, files[i]));
					}
				}
			} else {
				FileInputStream fis;
				try {
					fis = new FileInputStream(file);
				} catch (FileNotFoundException fnfe) {
					// at least on windows, some temporary files raise this exception with an "access denied" message
					// checking if the file can be read doesn't help
					return;
				}
				
				try {
					// make a new, empty document
					Document doc = new Document();
					
					// Add the path of the file as a field named "path".  Use a
					// field that is indexed (i.e. searchable), but don't tokenize 
					// the field into separate words and don't index term frequency
					// or positional information:
					Field pathField = new Field("path", file.getPath(), Field.Store.YES, Field.Index.NOT_ANALYZED_NO_NORMS);
					doc.add(pathField);
//					doc.add(new Field("title", "Title Test", Field.Store.YES, Field.Index.NOT_ANALYZED_NO_NORMS));
					
					// Add the last modified date of the file a field named "modified".
					// Use a NumericField that is indexed (i.e. efficiently filterable with
					// NumericRangeFilter).  This indexes to milli-second resolution, which
					// is often too fine.  You could instead create a number based on
					// year/month/day/hour/minutes/seconds, down the resolution you require.
					// For example the long value 2011021714 would mean
					// February 17, 2011, 2-3 PM.
					NumericField modifiedField = new NumericField("modified");
					modifiedField.setLongValue(file.lastModified());
					doc.add(modifiedField);
					
					// Add the contents of the file to a field named "contents".  Specify a Reader,
					// so that the text of the file is tokenized and indexed, but not stored.
					// Note that FileReader expects the file to be in UTF-8 encoding.
					// If that's not the case searching for special characters will fail.
					doc.add(new Field("contents", new BufferedReader(new InputStreamReader(fis, "UTF-8"))));
					
					if (writer.getConfig().getOpenMode() == OpenMode.CREATE) {
						// New index, so we just add the document (no old document can be there):
						System.out.println("adding " + file);
						writer.addDocument(doc);
					} else {
						// Existing index (an old copy of this document may have been indexed) so 
						// we use updateDocument instead to replace the old one matching the exact 
						// path, if present:
						System.out.println("updating " + file);
						writer.updateDocument(new Term("path", file.getPath()), doc);
					}
				} finally {
					fis.close();
				}
			}
		}
	}
}
